Portable terminal equipment

ABSTRACT

This invention relates to a portable terminal equipment which receives intermittently a control channel transmitted from a cell station in a standby state. When the equipment shifts to the standby state, the equipment is brought into a receiving state to receive intermittently the control channel (PCH) for a set period of time W1 at every 1.2 seconds (ST 22 -ST 25  and ST 32 ). In addition, the equipment judges the receiving state from judging information of the receiving state such as the intensity of the electric field in receiving time and the presence/absence of an error in the received data (ST 27  and ST 33 ). In a power saving mode, when the equipment keeps on receiving the control channel in a good state for a set period of time while the equipment receives the control channel at every 1.2 seconds, the equipment is brought into a receiving state to receive the control channel at every 2.4 seconds (ST 33 -ST 35 ). When the equipment does not receive the control channel in a good state while the equipment receives the control channel at every 2.4 seconds, the equipment shifts directly to the receiving state to receive the control channel at every 1.2 seconds (ST 33  and ST 32 ). In the standby state, when the equipment keeps on receiving the control channel in a good state, the interval between each reception of the control channel becomes longer and thus the power consumption of the equipment is saved.

TECHNICAL FIELD

The present invention relates to a portable terminal equipment such as aportable telephone or the like. In details, the present inventionrelates to a portable terminal equipment capable of saving powerconsumption by controlling the interval between each reception of thecontrol channel in a standby state on the basis of receiving state.

BACKGROUND OF THE INVENTION

In a simplified type portable telephone-such as PHS (Personal HandyphoneSystem), in the case of out-of-synchronism with a control channel, thesynchronism with the control channel is established by receiving thecontrol channel transmitted from a cell station and then a locationthereof is registered to the cell station and the telephone shifts to astandby state. In addition, in the standby state, the telephone receivesintermittently the control channel and obtains the data such as thearrival of incoming call.

The cell station, however, transmits the data such as the arrival ofincoming call, plural times in consideration of jamming and soon.Therefore, when the control channel is received in a good state, it hasno trouble that the interval between each reception of the controlchannel becomes longer.

Hence, it is an object of the present invention to provide a portableterminal equipment capable of saving the power consumption bycontrolling the interval between each reception of the control channelon the basis of the receiving state.

DISCLOSURE OF THE INVENTION

According to the present invention, there is provided a portableterminal equipment receiving intermittently a control channeltransmitted from a cell station in a standby state which comprises areceiving-state-judging means for judging whether or not said controlchannel is received in a good state, and a receiving control means forcontrolling an interval between each reception of said control channelon the basis of the result of judgment of the receiving-state-judgingmeans. Further, said receiving control means controls the interval sothat when said receiving-state-judging means judges that said controlchannel is kept on receiving in a good state for a predetermined periodof time while said control channel is received at every first interval,said control channel is made received at every second interval that islonger than said first interval; and said receiving control means alsocontrols the interval so that when said receiving-state-judging meansjudges that said control channel is not received in a good state whilesaid control channel is received at every said second interval, saidcontrol channel is made received at every said first interval.

Said receiving-state-judging means judges whether or not said controlchannel is received in a good state, based on an intensity of electricfield or the presence or absence of the error in the received data andso on. Further, the interval between each reception of the controlchannel is controlled according to the result of judgment by thereceiving-state-judging means. The equipment is controlled so that whensaid receiving-state-judging means judges that said control channel 3 iskept on receiving in a good state for a predetermined period of timewhile said interval between each reception of the control channel isshort, said interval is extended. The equipment is also controlled sothat when said receiving-state-judging means judges that said controlchannel is not received in a good state while said interval between eachreception of the control channel is long, said interval is shortened.

Where the interval between each reception of control channel is socontrolled that said interval becomes longer, saidreceiving-state-judging means judges, according to this invention, thatthe control channel is kept on receiving in a good state for apredetermined period of time while said interval between each receptionof the control channel is short. Therefore, this invention prevents theequipment from being so precipitately controlled that said intervalbecomes longer when the control channel is suddenly made received in agood state even though the control channel is not received in a goodstate on the whole.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing the constitution of a simplified typeportable telephone as a best mode of this invention.

FIG. 2 is a front view showing the simplified type portable telephone(where a key-protecting lid is detached).

FIG. 3 is a side view showing the simplified type portable telephone.

FIG. 4 is a diagram showing the constitution of a logical controlchannel (LCCH).

FIG. 5 is a diagram showing the constitution of BCCH.

FIG. 6 is adiagram showing the constitution of SCCH.

FIG. 7 is a diagram showing the constitution of PCH.

FIG. 8 is a flowchart showing an example for controlling the intervalbetween each reception of the control channel in the standby state ofthe telephone.

FIG. 9 illustrates a drawing showing waveform of consumed current in astandby state of the telephone.

FIG. 10 a flowchart showing other example for controlling said intervalin the case where synchronism with the control channel is made off.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows a simplified type portable telephone 10 according to anembodiment as the best mode of this invention. The telephone 10 uses abattery as its power source.

The telephone 10 is provided with a microcomputer 11 for controlling asystem, an antenna 12 for the transmission and reception of signal, awireless unit 13 downconverting a receiving signal at a predeterminedfrequency caught by the antenna 12 to provide a π/4 shift QPSK(Quadrature Phase Shift Keying) signal and upconverting a π/4 shift QPSKsignal outputted from a digital modulating and demodulating unit 14,mentioned later, to provide a transmitting signal at a predeterminedfrequency, and the digital modulating and demodulating unit 14demodulating the π/4 shift QPSK signal outputted from the wiring unit 13to provide the receiving data and modulating the transmitting dataoutputted from a TDMA (Time Division Multiple Access) processing unit,mentioned later, to provide the π/4 shift QPSK signal.

The telephone 10 is also provided with the TDMA processing unit 15 forselecting the data of down slots which are previously set, from areceiving data (time division multiplex data in a plurality of slots)outputted from the digital modulating and demodulating unit 14, forseparating the data into control data and compressed voice data and formultiplexing the compressed voice data outputted from a voice codecunit, mentioned later, and the control data outputted from themicrocomputer 11 to the up slots which are previously set.

Further, the telephone 10 is provided with the voice codec unit 16 forcarrying out decoding processing (including error correcting processing)in respect of the compressed voice data outputted from the TDMAprocessing unit 15 to provide a receiving voice signal and for carryingout compressed code forming processing (including an additionalprocessing of the error correcting processing) in respect of atransmitting voice signal to provide the compressed voice data, aspeaker (receiver) 17 for being supplied with the receiving voice signaloutputted from the voice codec unit 16 and a microphone (transmitter) 18for supplying a transmitting voice signal to the voice codec unit 16.

Additionally, the telephone 10 is provided with a DTMF modulating anddemodulating unit 19 for converting a DTMF (Dual Tone MultipleFrequency) signal provided at the voice codec unit 16 as a receivingvoice signal into key data in correspondence with special input keyssuch as “*” and “#” or ten keys of “0” through “9” to supply the data tothe microcomputer 11 and for converting the key data in correspondencewith special input keys such as “*” and “#” or ten keys of “0” through“9” outputted from the microcomputer 11 into the DTMF signal to supplyit to the voice codec unit 16 as a transmitting voice signal, and aconversion format storing unit 20 for converting the key data outputtedfrom the DTMF modulating and demodulating unit 19 into character data.The conversion format storing unit 20 is connected to the microcomputer11.

Still further, the telephone 10 is provided with a voice recording andreproducing unit 21 for recording a receiving voice signal provided bythe voice codec unit 16 and for reproducing a recorded receiving voicesignal or a previously recorded answer message (voice signal)byoperationof a key input unit, mentioned later, or control of themicrocomputer 11 in an absence recording mode, a vibration generatingunit 22 for vibrating a telephone main body by control of themicrocomputer 11 when a signal is received in the case where a vibrationmode is set, and an alerting sound output unit 23 for outputtingalerting sound by control of the microcomputer 11 when a signal isreceived in the case where the vibration mode is not set. In this case,the voice recording and reproducing unit 21 is provided with, forexample, a semiconductor memory as a storage medium for a voice signal.Operation of the voice recording and reproducing unit 21 is controlledby the microcomputer 11 and a signal indicating the operational state ofthe voice recording and reproducing unit 21 is supplied from the unit 21to the microcomputer 11.

Further, the telephone 10 is provided with the key input unit 24arranged with a speaking key for instructing an outgoing call or forresponding when an incoming call is arrived, a speech termination keyfor terminating speech, a function key for shifting to a telephone bookregistering mode and for setting an absence recording mode, a vibrationmode or a power saving mode and so on, ten keys and special input keysfor inputting a telephone number or the like and a recording key, areproducing key and a sound volume key so on each of which is providedfor operating the recording and reproducing of the voice recording andreproducing unit 21. The key input unit 24 is connected to themicrocomputer 11 and key operation of the key input unit 24 is monitoredby the microcomputer 11.

Further, the telephone 10 is provided with a non-volatile memory 25 forstoring telephone book data, redial data, character message datatransmitted from the called party, mode setting information and so on, atimer unit 28 for counting a time period from an arbitrary time point bycontrol of the microcomputer 11 and a liquid crystal display (LCD:Liquid Crystal Display) 26 for displaying a state of a system, thetelephone number of the called party in calling and character messagetransmitted from the called party and so on. The liquid crystal display26 is driven by an LCD driver 27 controlled by the microcomputer 11.

FIG. 2 and FIG. 3 show the outlook of the telephone 10 and the samenotations attaching thereto show portions in correspondence with thosein FIG. 1.

The antenna 12 is arranged at the upper end portion of a telephone mainbody 40. Further, voice passing holes 41 for leading out voice from abuilt-in speaker to outside is formed at an upper portion of the mainbody 40 and the liquid crystal display 26 is arranged thereunder.Further, the microphone 18 is arranged at a lower portion of the mainbody 40. Further, a speaking key 42, a function key 43 and a speechtermination key 44 are arranged to align laterally at a central portionof the main body 40 and on the lower side of the liquid crystal display26. The termination key 44 constitutes a power ON/OFF key when it ispushed for a long period of time.

Additionally, cursor moving keys 45 for moving the cursor up and down toright and left, a registration key 46 for registering a telephone book,a clear key 47 for clearing input data, ten keys 48 and special inputkeys 49 and 50 are arranged on the lower side of the keys 42 through 44.In this case, “↑” key constituting the cursor moving key 45 serves alsoas a key for initiating the search of redial data or telephone book dataand “↓” key serves also as a key for shifting to a charactertransmitting mode during a telephone communication and for confirmingthe received character data.

Further, the main body 40 is arranged with a key-protecting lid 51,which is constituted openably and closably with a portion of arrangingthe microphone 18 as a fulcrum. By closing the key-protecting lid 51,the keys 45 through 50 are covered. Therefore, it is necessary tooperate the keys 45 through 50 in a state where the key-protecting lid51 is opened. Incidentally, FIG. 2 shows a telephone in a state wherethe key-protecting lid 51 is removed.

Further, a recording key 52 and a reproducing key 53 each of which isprovided for operating recording and reproducing of the voice recordingand reproducing unit 21 (see FIG. 1) and a sound volume adjusting key 54for adjusting sound volume, are arranged at a side face of the main body40. The sound volume adjusting key 54 is constituted such that when +side thereof is operated to push, the sound volume is increased andconversely, when − side is operated to push, the sound volume isreduced.

Next, an explanation will be given of the operation of the telephone 10shown by FIG. 1.

When the power source is made ON, the telephone is brought to a statewhere the synchronism with a control channel is made off andaccordingly, establishment of synchronism with the control channel iscarried out after receiving the control channel transmitted from a cellstation. Further, thereafter, location registration indicating that thetelephone stays within the service area of the service station, iscarried out. The location registration is carried out by using aspeaking channel. After finishing the location registration, thetelephone returns to the receiving state of control channel and isbrought into a standby state.

FIG. 4 shows an example of the constitution of a logical control channel(LCCH). Incidentally, this is an example in which a first slot of a TDMAframe is allocated to the logical control channel (LCCH) and an LCCHsuper frame is constituted by m of intermittently transmitted frames atevery nTDMA frames.

According to slots to be used by a cell station (CS), a TDMA frame of 5[ms] is constituted by 4 slots of down (transmission) and 4 slots of up(reception) successive thereto. Further, slots constituting a downlogical control channel (LCCH) are present at every nTDMA frame. Thatis, a down intermittent transmitting period is 5×n [ms].

Further, a minimum period (5×n ×m [ms]) of a down logical controlchannel (LCCH) designating slot positions of all of LCCH elements isdefined as an LCCH super frame. The down logical control channel (LCCH)is constituted by a broadcast control channel (BCCH), a paging channel(PCH) and a signaling control channel (SCCH). BCCH is transmitted atfront slots of the LCCH super frame and a position of a front of LCCHsuper frame is informed by transmitting BCCH. In the meantime, an uplogical control channel (LCCH) is constituted by a signaling controlchannel (SCCH). A position of a slot in the up logical control channel(LCCH) is informed from the cell station (CS) to a personal station (PS)by information elements constituting a carrier for control in a messagefor the broadcast information of wireless channel on BCCH.

FIG. 5 shows the constitution of BCCH. BCCH is a down uni-directionalchannel for informing broadcast control information from CS to PS.Information related to channel structure, system information and so onis transmitted by BCCH.

BCCH is constituted by a preamble pattern (PR), a unique word forsynchronization (UW), a channel identifier (CI), a transmissionidentification code, data (BCCH) and a cyclic redundancy check (CRC).Further, the transmission identification code is constituted by anoperator identification code, a paging area number and an additional ID.Further, data (BCCH) is constituted by octet 1 through octet 8. Further,kind of message by octet 2 through octet 8 is shown by lower 7 bits ofoctet 1.

FIG. 6 shows the constitution of SCCH. SCCH is a point-to-pointbi-directional channel for transmitting information necessary forconnecting call between CS and PS. According to SCCH, independentinformation is transmitted to each cell.

SCCH is constituted by a preamble pattern (PR), a unique word forsynchronization (UW), a channel identifier (CI), a transmissionidentification code, a reception identification code, data (SCCH) and acyclic redundancy check (CRC). Further, according to SCCH (down), thetransmission identification code is constituted by an operatoridentification code, a paging area number and an additional ID and thereception identification code is constituted by a PS identification(PS-ID). Although not illustrated, according to SCCH (up), thetransmission identification code mentioned above is constituted as thereception identification code and the reception identification codementioned above is constituted as the transmission identification code.Data (SCCH) is constituted by octet 1 through octet 5. Further, kind ofmessage by octet 2 through octet 5 is shown by lower 7 bits of octet 1.

PCH is a down uni-directional channel of point-to-multi-points forpaging the same information from CS to PSs over a wide area (pagingarea) composed of a single cell and/or a pluralityof cells. ByPCH, CSinforms to PS that call is-present. As shown by FIG. 4, a plurality ofnumber of PCHs (PCH1 through PCHn) is present in the LCCH super frame.

FIG. 7 shows the constitution of PCH. PCH is constituted by a preamblepattern (PR), a unique word for synchronization (UW), a channelidentifier (CI), a transmission identification code, data (PCH) and acyclic redundancy check (CRC). Further, the transmission identificationcode is constituted by an operator identification code, a paging areanumber and an additional ID. Further, the data (PCH) is constituted byoctet 1 through octet 8.

In this case, PCH defines only a single message and therefore, PCH isnot provided with an area indicating kind of message. Kind of callservice such as no call, a call service by a PS number indicated by athirteenth digit or lower of BCD, call service by a PS number ofhexadecimal seven digit or the like is displayed by 5 through 7 bits ofoctet 1. Further, the PS number is shown by octets 1 through 7. Further,reception instruction of a broadcast control channel (BCCH) is carriedout by octet 8. When there causes a change in an intermittent reception,mentioned later, PS receives BCCH by the reception instruction.

Further, PS recognizes PCH to be received from a plurality of PCHs (PCH1through PCHn) by a reception signal group number. In respect of PS, thereception signal group number is calculated by Equation (1) based on PSnumber and content of BCCH from CS (n_(PCH), n_(GROUP), constitution ofa carrier for control). In this equation, notation n_(PCH) designates anumber of same reception signal group and notation n_(GROUP) designatesa reception signal group factor. Further, when two frequencies (2LCCH)are used and the reception groups of PCH relate to each other, X=2 andotherwise X=1.

Reception signal group number =(PS No.)MOD(n_(PCH)×n_(GROUP)×X)+1  (1)

As described above, after finishing location registration, the systemreturns to its control channel receiving state and is brought into astandby state. In the standby state, the telephone (PS) 10 is shifted tointermittent receiving in which only PCH in correspondence with thecalculated reception signal group number is received. In this case, PCHin correspondence with the calculated reception signal group number ispresent at every LCCH super frame and accordingly, intermittentreceiving at every 1.2 seconds is formerly constituted in the standbystate.

As described before, the cell station, however, transmits the data suchas the arrival of incoming call, plural times in consideration ofjamming and so on. Therefore, when the control channel is received in agood state, it has no trouble that the interval between each receptionof the control channel becomes longer.

In this embodiment, the microcomputer 11 controls the interval betweeneach reception of the control channel in accordance with a flowchartshown by FIG.8.

When the telephone shifts to the standby state, the telephone is timedto the reception timing of PCH of the reception signal number calculatedthe above. Firstly, at step ST21, the timer 1 is started and, at stepST22, the timers 2 and 3 are also started. In this case, each of thetimers 1 through 3 is constituted by the timer unit 28 and they arereset at starting operation.

Next, at step ST23, receiving circuits such as the wireless unit 13, thedigital modulating and demodulating unit 14, the TDMA processing unit 15are brought into an ON state. Further, at step ST24, it is determinedwhether time period W1 has elapsed referring to the timer 2. In thiscase, the time period W1 is a time period for recieving control channelat each time in the intermittent reception and is set to, for example,48 ms. When the time period W1 has elapsed, at step 25, the receivingcircuits are brought into an OFF state. Further, at step ST26, it isdetermined whether or not the control channel (PCH) has been receivedfrom the cell station while the receiving circuits stay on the ON state.

At step ST26, when the control channel (PCH) is received, at step ST27,the information for the judgment of receiving state is stored in thebuilt-in memory. As the information for the judgment of receiving state,the information such as the intensity of electric field on the occasionof receiving the control channel (PCH), the presence or absence of anerror in the received data and so on, is exemplified.

Next, at step ST28, it is determined whether or not the PS number of PCHis mine. When said PS number is mine, at step ST29, the processing ofthe arrival of incoming call is carried out. When said PS number is notmine, at step ST30, it is determined whether or not the power savingmode is set. When the power saving mode is not set, at step ST31, thetimer 1 is started and the operation proceeds to step ST32.

When, at step ST30, the power saving mode is set, at step ST27, it isdetermined whether or not the control channel is received in a goodstate on the basis of the information for the judgment of receivingstate, which has been stored in the build-in memory at step ST27. Whenthe good receiving state of the control channel is determined by theinformation such that the intensity of electric field is high and thereis no error in the received data, at step ST34, it is determined whetheror not a predetermined period of time has elapsed referring to the timer1. When the predetermined period of time has not elapsed, the operationproceeds to the step ST32. When, at step ST33, the good receiving stateis not determined, at step ST31, the timer 1 is started and then theoperation proceeds to the step ST32.

At the step ST32, it is determined whether or not 1.2 seconds haveelapsed referring to the timer 3. When 1.2 seconds have elapsed, theoperation returns to the step ST22 in which the receiving circuits arebrought into ON state, and then the operations described above arerepeated.

When, at step ST34, the predetermined period of time has elapsed, atstep ST35, it is determined 2.4 seconds have elapsed. When 2.4 secondshave elapsed, the operation returns to the step ST22 and the timers 2and 3 are started, and then the operations described above are repeated.

When, at step ST26, the control channel (PCH) is not received from thecell station while the receiving circuits stay on the ON state,out-of-synchronism with the control channel is judged and then, at stepST36, the processing of out-of-synchronism is carried out.

When the power savingmode is not set like this, the control channel(PCH) is received at every 1.2 seconds in spite of the receiving state.Alternatively, in case where the power saving mode is set, when thecontrol channel is kept on receiving in a good state for a predeterminedperiod of time while said control channel is received at every 1.2seconds, said control channel is made received at every 2.4 seconds.Further, when the control channel is not received in a good state whilesaid control channel is received at every 2.4 seconds, said controlchannel is promptly made received at every 1.2 seconds.

Therefore, when the control channel is kept on receiving in a good statein the standby state of the telephone, the interval between eachreception of the control channel becomes longer and thus the powerconsumption is saved and the consumption of a battery can be prevented.

Where the interval between each reception of control channel is socontrolled that said interval becomes longer, saidreceiving-state-judging means judges, according to this invention, thatthe control channel is kept on receiving in a good state for apredetermined period of time while said interval is short. Therefore,according to this invention, such a precipitate control that saidinterval becomes longer when the control channel is suddenly madereceived in a good state even though the control channel is not receivedin a good state on the whole, does not occur.

FIG. 9 shows waveform of consumed current in the operation by theflowchart of FIG. 8. In this case, the notation T1 designates the timewhen it is judged that the control channel is kept on receiving in agood state for a predetermined period of time while said control channelis received at every 1.2 seconds. The notation T2 designates the timewhen it is judged that the control channel is not received in a goodstate while said control channel is received at every 2.4 seconds. Inthis case, the consumed current is I1 (for example, 4 ma) when thereceiving circuits stay on the OFF state and the consumed current is I2(for example, 180 ma) when the receiving circuits stay on the ON state.

The microcomputer 11 controls the processing of out-of-synchronism atstep ST36 in accordance with a flowchart shown by FIG. 10.

First, at step ST1, M=0 is set and at step ST2, N=X+5 is set. Notation Mdesignates a number of bringing about the control channel receivingstate in order to establish the synchronism with the control channel(i.e., number of retrial) and notation X designates a number ofout-of-synchronism during past one hour. Next, at step ST3, receivingcircuits such as the wireless unit 13, the digital modulating anddemodulating unit 14, the TDMA processing unit 15 are brought into an ONstate and at step ST4, a timer is started. In this case, the timer isconstituted by the timer unit 28 and is reset in starting operation.

Next, at step ST5, it is determined whether a time period W2 haselapsed. In this case, the time period W2 is a reception time period toreceiving control chanel at each time in the intermittent reception inthe case of out-of-synchronism and is set to, for example, 220 ms. Whenthe time period W2 has elapsed, at step ST6, the receiving circuits arebrought into an OFF state. Further, at step ST7, it is determinedwhether the synchronismwith the control channel has been established byreceiving the control channel from the cell station while the receivingcircuits stay on the ON state.

When, at step ST7, it is determined that the synchronism with thecontrol channel has not been established, at step ST8, M is incrementedand, at step ST9, a timer is started. Further, at step ST10, it isdetermined whether a time period t1 has elapsed. The time period t1 isan interval between each reception of the control channel and, accordingto the embodiment, is set to, for example, 6 seconds. At step ST11, itis determined whether M>N is determined where the time period t1 haselapsed.

When M>N is not established in step ST11, the operation returns to stepST3 and then the receiving circuits are brought into the ON state andthe operations as described above are repeated. When M>N at step ST11,at step ST12, the receiving circuits are brought into the ON state andthen, at step ST13, a timer is started.

Next, at step ST14, it is determined whether the time period W2 haselapsed. When the time period W2 has elapsed, at step ST15, thereceiving circuits are brought into the OFF state. Further, at stepST16, it is determined whether the synchronism with the control channelhas been established by receiving the control channel from cell stationwhile the receiving circuits stay on the ON state. When, at step ST16,it is determined that the synchronism with the control channel has notbeen established, at step ST17, a timer is started.

Next, at step ST18, it is determined whether a time period t2 haselapsed. The time period t2 is an interval between each reception ofcontrol channel and, according to the embodiment, it is set to, forexample, 30 seconds. When the time period t2 has elapsed, the operationreturns to the step ST12 and the receiving circuits are brought into theON state and then the operations as described above are repeated.

Further, when, at step ST7, the control channel has been established, atstep ST19, the location is registered and, at step ST20, the systemshifts to the standby state.

According to the operation by the flowchart of FIG. 10, the morefrequently a user moves, the larger the number X of out-of-synchronismbecomes and accordingly, N becomes larger by that amount and a period oftime until the interval t1 (6 seconds) between each reception of controlchannel is changed to the interval t2 (30 seconds), is prolonged.

Therefore, where a user moves frequently and moves back highly probablyinto the service area of the cell station even if the user moves outsideof the service area of the cell station, the receiving state of controlchannel is frequently brought about and where the user moves back intothe service area of the cell station, the establishment of thesynchronism with the control channel is swiftly carried out. In themeantime, where the user moves infrequently, and a possibility where theuser moves back into the service area of the cell station again aftermoving outside of the service area of the cell station, is low, thefrequency of bringing about the receiving state of control channel islowered and thus emphasis is put on preventing a battery from itsconsumption. Accordingly, consumption of a battery can be prevented incompliance with situation of moving of a user.

Further, according to the telephone 10 shown by FIG. 1, when telephonenumber of called party is inputted by key operation at the key inputunit 24 (ten keys 48 or the like), or the speaking key 42 is operatedafter searching redial data or telephone book data, firstly, telephonenumber data or the like are supplied to the TDMA processing unit 15 ascontrol data by the microcomputer 11 and are transmitted to the cellstation via the control channel. Thereby, telephone communication ismade to the called party and a speaking state is brought about.

In this case, although telephone communication is carried out by usingthe speaking channel, in processing the connection, the communicationfrequency data of the speaking channel and the data relating to the slotpositions each of which are transmitted as control data from the cellstation by using the control channel, are supplied to the microcomputer11 via the TDMA processing unit 15. The microcomputer 11 makes thetransmission and reception frequency coincide with the communicationfrequency of the speaking channel by controlling the wireless unit 13based on the communication frequency data and sets slots selected by theTDMA processing unit 15 on the basis of the slot position data.Accordingly, telephone communication is carried out by using thespeaking channel informed from the cell station.

Further, in the case that call data is supplied to the microcomputer 11via the TDMA processing unit 15 and the arrival of incoming call isdetected when the call data is transmitted as control data from the cellstation by using the control channel, the alerting sound output unit 23is controlled by the microcomputer 11 and thus the alerting sound isoutputted thereby. Alternatively, the telephone main body 40 is vibratedby controlling the vibration-generating unit 22 by the microcomputer 11.

When the speaking key 42 is operated and a response is produced whilesuch the call operation is being carried out, response data is suppliedas control data from the microcomputer 11 to the TDMA processing unit 15and is transmitted to the cell station via the control channel. Thereby,the connection with the called party is carried out and the speakingstate is brought about. Also in this case, telephone communication iscarried out by using the speaking channel informed from the cellstation.

In the speaking state, compressed voice data transmitted via thespeaking channel is outputted from the TDMA processing unit 15. Thecompressed voice data is supplied to the voice codec unit 16, subjectedto a decoding processing and thereafter converted into an analog signal.Further, the received voice signal outputted from the voice codec unit16 is supplied to the speaker 17 and voice is outputted from the speaker17.

Further, a transmitting voice signal outputted from the microphone 18 issupplied to the voice codec unit 16, converted into a digital signal andthereafter subjected to compressed code forming processing wherebycompressed voice data is formed. Further, the compressed voice dataoutputted from the voice codec unit 16 is supplied to the TDMAprocessing unit 15 and is transmitted to the called party via thespeaking channel.

In this case, by operating “↓” key of the cursor moving key 45,transmission of character data can be carried out by using the ten keys48 or the special input keys 49 and 50. In this case, DTMF signals incorrespondence with the operated keys are outputted from the DTMFmodulating and demodulating unit 19 and is supplied to the voice codecunit 16 as a transmitting voice signal.

Further, when the telephone is set to an absence recording mode in thecase where the call data are supplied from the TDMA processing unit 15to the microcomputer 11 and the arrival of incoming call is detected asmentioned above, a response is made automatically after outputtingalerting sound for a predetermined period of time, and the speakingstate is brought about. Further, after transmitting to the calling sidethe response message that a received voice signal will be recorded,recording of the received voice signal is started at the voice recordingand reproducing unit 21.

Further, when character message data by a DTMF signal are transmittedfrom the called party during an absence recording or during a telephonecommunication, key data outputted from the DTMF modulating anddemodulating unit 19 is converted into character data based on controlof the microcomputer 11 in reference to the conversion format storingunit 20 and the character data is written to a character message area ofthe non-volatile memory 25. When the character data is written to thenon-volatile memory 25 in this way, the character message of thecharacter data is displayed on the liquid crystal display 26 and can beconfirmed by operating to push “↑” key of the cursor moving key 45 for along period of time.

Although, in the flowchart shown in FIG.8, the control channel is madereceived at every 2.4 seconds when the control channel is kept onreceiving for a predetermined period of time while the control channelis received at every 1.2 seconds, the control channel may be received atevery n times of 1.2 seconds such as three times, four times, in steadof 2.4 seconds. Further, when the control channel is kept on receivingfor a predetermined period of time, the interval between each receptionof control channel may extend by degrees such as 1.2 seconds→2.4seconds→3.6 seconds→ . . . , at every set period of time.

Further, although according to the above-described embodiments, thepresent invention is applied to a simplified type portable telephone,the present invention is naturally applicable similarly to otherportable terminal equipment which is capable of receiving intermittentlythe control channel transmitted from the cell station in a standbystate.

INDUSTRIAL APPLICABILITY

As described above, a portable terminal equipment according to thepresent invention is preferably applied to a portable terminal equipmentof a simplified type portable telephone or the like, which is capable ofreceiving intermittently the control channel transmitted from the cellstation in a standby state.

What is claimed is:
 1. A portable terminal equipment receivingintermittently a control channel transmitted from a cell station in astandby state comprising: a receiving-state-judging means-for-judgingwhether or not said control channel is received in a good state; and areceiving control means for controlling an interval between eachreception of said control channel on the basis of the result of judgmentof the receiving-state-judging means; wherein said receiving controlmeans controls the interval so that when said receiving-state-judgingmeans judges that said control channel is kept on receiving in a goodstate for a predetermined period of time while said control channel isreceived at every first interval, said control channel is made receivedat every second interval, said second interval being longer than saidfirst interval; and wherein said receiving control means controls theinterval so that when said receiving-state-judging means judges thatsaid control channel is not received in a good state while said controlchannel is received at every said second interval, said control channelis made received at every said first interval.
 2. A portable terminalequipment according to claim 1: wherein said receiving control meanscontrols the interval so that when said receiving-state-judging meansjudges that said control channel is not received in a good state whilesaid control channel is received at every said second interval, saidcontrol channel is promptly made received at every said first interval.3. A portable terminal equipment according to claim 1: wherein saidsecond interval is n times said first interval, where n is an integernot less than two.
 4. A portable terminal equipment according to claim1: wherein said receiving-state-judging means judges said receivingstate on the basis of an intensity of electric field.
 5. A portableterminal equipment according to claim 1: wherein saidreceiving-state-judging means judges said receiving state on the basisof the judgment whether or not there is an error in the received data.6. A portable terminal equipment according to claim 1 comprising: asetting means for setting a power saving mode; wherein said receivingcontrol means controls the interval between each reception of saidcontrol channel on the basis of the result of judgment of thereceiving-state-judging means when said setting means sets said powersaving mode; and wherein said receiving control means controls theinterval between each reception of said control channel so that saidinterval is held constant regardless of the result of judgment of thereceiving-state-judging means when said setting means does not set saidpower saving mode.